[BrianR]

But unless the OP utilizes Focus Stacking, which his KP brings along as a separate feature,

Depth of Field Bracketing is useful for macro. But only three shots are not much enough for focus stacking.
Pentax KP Review - Drive Modes and Flash | PentaxForums.com Reviews

The Kp has DoF Bracketing which takes multiple photos at the same focus distance but changes the aperture (and not the overall exposure). This is neither Focus Stacking nor even Focus Bracketing which would let you stack later in post. Focus Stacking for a landscape would need to be done manually by turning the focus ring between photos, and it's definitely a viable option (at the cost of time).

[Madaboutpix]

The Kp has DoF Bracketing which takes multiple photos at the same focus distance but changes the aperture (and not the overall exposure). This is neither Focus Stacking nor even Focus Bracketing which would let you stack later in post.

Thanks for the correction, Brian. Somehow - wishful thinking? - I was under the impression that such a desirable mode as Focus Bracketing had already made it into the newer Pentax models. Some Olympus and Panasonic shooters are getting this as a camera feature, I believe, and I think it's pretty cool. (Anybody listening, Ricoh?)

You're doing some amazing photography, by the way, Brian. Will return to your blog as soon as time allows to check out some more.

[photoptimist]

You sure love your exact numbers, and you're entitled to them. In fact, no one argues that numbers wouldn't matter in photography.

However, from a compositional standpoint, many landscape shots done with wide- and ultra-wideangle lenses benefit from including foreground interest, and those objects will be considerably closer than your 100 metres.

As for the concept of hyperfocal distance, I've grown a little doubtful about its ultimate usefulness in digital photography since I read this (as far as I can tell) pretty well-reasoned article:

Why Hyperfocal Distance Charts Are Wrong

Also, you might be a little too dismissive about focus stacking with a small number of exposures in landscape photography. I recall several landscape photographers, including our Veteran Pentaxian Mike Orea (mikeSF - View Profile - PentaxForums.com), who seem to be getting great results this way, though I can't attest he is using a KP.

That article uses a strawman argument. The hyperfocal distance is not wrong but it is often misunderstood and misapplied at two levels.

First, each photographer has their own definition of "acceptable sharpness" which they might have based on either pixel-peeping or overall impressions of the image on a certain print size or screen size. Hyperfocal distance depends on the photographer's chosen value for the CoC (circle of confusion) which varies with camera resolution (including the use of pixel shift) and the photographer's subjective tastes for sharpness. If a photographer uses a hyperfocal distance chart but feels like the ends of the range are too soft, then they just need to recompute the chart with a smaller CoC. And if the photographer thinks the chart is too conservative, then they should recompute it with a larger CoC.

Second, the chart only tells you what will be in focus (not what should be in focus or that you should always use hyperfocal distance focusing). It's up to the photographer to determine if the hyperfocal distance range works with the scene or whether: 1) they need a narrower aperture and hyperfocal distance to bring the foreground into focus; 2) they need a wider aperture to intentionally throw the foreground out of focus; 3) they need to use focus stacking (which actually uses the same hyperfocal distance math to estimate a good focus stack); or 4) they need to crop or reframe the shot to remove problematic foreground matter.

It's certainly true that many wide-angle landscape compositions have everything from a few feet away to infinity in the frame. But rather than waste time with trial-and-error combinations of aperture and lens distance settings hoping to get everything in focus, a hyperfocal distance chart calculated for the photographer's preferred CoC tells them exactly what they need to use to get shot (or if the shot is impossible with an acceptable aperture).

One general issue with all the "rules" of aperture, shutter speed, and ISO for photography is that they are merely starting points or guidelines, not black-and-white edicts. Each photographer needs to test how the rule works for them. Any time a photographer is learning a new technique like hyperfocal distance, the first step is to try it with a bit of bracketing and a bit more scrutiny to see if the rule needs a bit of tweaking. Often they will learn that they need to adjust the rule by a stop or two in some direction but that they can still use the rule.

[Madaboutpix]

That article uses a strawman argument. The hyperfocal distance is not wrong but it is often misunderstood and misapplied at two levels.

Well, the main problem may well be the unnecessarily strong or dismissive wording "wrong" in the author's discussion of hyperfocal distance. Catchy headlines make for clicks, but may be somewhat misleading. Yet his "double-distance" rule of thumb struck me as easy to remember and to apply in the field, particularly for photographers who don't bother to carry written charts for everything or enjoy the occasional smartphone abstinence. As with most photography rules, it is a mere starting point - no more, no less - and depending on the situation there may arise the need to adjust it. After years of shooting specific lenses, you get to the point of doing so quite intuitively, without significant harm of your keeper rate. At least, that would be my informal experience.

[photoptimist]

Well, the main problem may well be the unnecessarily strong or dismissive wording "wrong" in the author's discussion of hyperfocal distance. Catchy headlines make for clicks, but may be somewhat misleading. Yet his "double-distance" rule of thumb struck me as easy to remember and to apply in the field, particularly for photographers who don't bother to carry written charts for everything or enjoy the occasional smartphone abstinence. As with most photography rules, it is a mere starting point - no more, no less - and depending on the situation there may arise the need to adjust it. After years of shooting specific lenses, you get to the point of doing so quite intuitively, without significant harm of your keeper rate. At least, that would be my informal experience.

Excellent points! It sad how everyone has spread lies to get clicks these days.

The double distance rule is brilliant but it's different than the hyperfocal distance.

The double distance rule really does make the foreground objects just as sharp (or blurry) as infinity objects. But it provide no guarantee that both will be in focus. Double distance only works if that double-distance value happens to be greater than the hyperfocal distance for that focal length and aperture. There's no gaurantee of that so people still need to be aware of the hyperfocal distances.

[BrianR]

Thanks for the correction, Brian. Somehow - wishful thinking? - I was under the impression that such a desirable mode as Focus Bracketing had already made it into the newer Pentax models. Some Olympus and Panasonic shooters are getting this as a camera feature, I believe, and I think it's pretty cool. (Anybody listening, Ricoh?)

Focus bracketing is also landing in Nikon land. I expect (and hope!) focus bracketing/stacking will become a 'me too' feature and everyone will follow suit. I've wanted at least a bracketing version for years.

You're doing some amazing photography, by the way, Brian. Will return to your blog as soon as time allows to check out some more.

Thank you for looking and the feedback

[Bui]

Hello,

Thank you so much for all advises. The lens is on its way to a repair service. I'll know soon.

As my next trip is coming soon, I don't have time to wait, therefore I take another used 15mm as "trial" (I can return it if it's not ok), I would like to bring it with me instead of the 16-50, it's too bulky for a low-cost trip.

I took some quick test photos this morning, and realized that the new lens, though being better, is still quite soft at the edges, as compared with the DA*. I know the 15 Ltd is well known for weak corner, but I'm not sure if my new lens is working as designed, or this copy is still not sufficient. The DA* is not so stellar at 16mm, yet is still quite sharper.

The first photo was taken with the 15mm, the second one with the DA*, both f.8, tripod, and JPG SOOC. Anyone owning this lens can you help me to look at it? I really like the color and contrast in its photos though.

DA15mm: https://www.flickr.com/photos/160977434@N05/39871753670/in/dateposted-public/

DA* 16-50: https://www.flickr.com/photos/160977434@N05/39871731130/in/dateposted-public/

Thank you again